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Weed Control in Maize (Zea mays L.) Through SorghumAllelopathyZ. A. Cheema a , A. Khaliq b & S. Saeed ca Department of Agronomy , University of Agriculture , Faisalabad, 38040, Pakistan E-mail:b Department of Agronomy , University of Agriculture , Faisalabad, 38040, Pakistan E-mail:c Ward # 10, Siddiqabad, Kot Addu, Muzzafargarh, PakistanPublished online: 24 Sep 2008.

To cite this article: Z. A. Cheema , A. Khaliq & S. Saeed (2004) Weed Control in Maize (Zea mays L.) Through SorghumAllelopathy, Journal of Sustainable Agriculture, 23:4, 73-86, DOI: 10.1300/J064v23n04_07

To link to this article: http://dx.doi.org/10.1300/J064v23n04_07

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Weed Control in Maize (Zea mays L.)Through Sorghum Allelopathy

Z. A. CheemaA. KhaliqS. Saeed

ABSTRACT. Sorghum allelopathy has been utilized as an economicaland natural technique for controlling weeds in some field crops like wheat(Triticum aestivum L.), maize (Zea mays L.), rice (Oryza sativa L.),mungbean (Vigna radiata L.) and Brassica (Brassica juncea L.). It can beused as sorgaab (water extract of mature sorghum plants), sorghummulch, sorghum soil incorporation or included in crop rotation. Two fieldexperiments were conducted for two years in the summer of 1997 and1998. In Experiment 1, the response of maize (Zea mays L.) and summerweeds to foliar applications of sorgaab, hand weeding and herbicide spraywas studied. In Experiment 2, the comparative efficacy of sorgaab at 15, 30and 45 days after sowing (DAS) and sorghum mulch for controlling weedswere studied. Sorgaab foliar spraying controlled from 18-50% weeds andincreased maize grain yield by 11-44%. Mature and chaffed sorghum herb-age (10-15 Mg ha�1) surface applied at sowing controlled up to 26-37%weeds and increased maize yield by 36-40%. Three foliar sprays of sorgaabat 15, 30 and 45 days after sowing was the most economical method forcontrolling weeds in maize as compared with hand weeding, chemicalherbicides and sorghum mulch. Weed control through hand weeding and/or chemical herbicides was found to be economically impractical due tohigher costs involved in both cases. Sorgaab can be used as a natural weedinhibitor in maize. Article copies available for a fee from The Haworth Docu-ment Delivery Service: 1-800-HAWORTH. E-mail address: <docdelivery@haworthpress.com> Website: <http://www.HaworthPress.com> 2004 by TheHaworth Press, Inc. All rights reserved.]

Please note that this electronic prepublication galley may contain typographical errors and may be missingartwork, such as charts, photographs, etc. Pagination in this version will differ from the published version.

Z. A. Cheema is Professor and A. Khaliq is Assistant Professor, Department ofAgronomy, University of Agriculture, Faisalabad-38040, Pakistan (E-mail: zacheema@pakwatan.com, or khaliqauf@hotmail.com).

S. Saeed is affiliated with Ward # 10, Siddiqabad, Kot Addu, Muzzafargarh, Pakistan.

Journal of Sustainable Agriculture, Vol. 23(4) 2004http://www.haworthpress.com/web/JSA

2004 by The Haworth Press, Inc. All rights reserved.Digital Object Identifier: 10.1300/J064v23n04_07 73

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KEYWORDS. Sorghum, sorgaab, mulch, allelopathy, weed control,maize

INTRODUCTION

Controlling weeds with allelopathic crop residues was first postulated byPutnam and Duke in 1974. Since then, efforts in various parts of the worldhave been underway to exploit the allelopathic potential of different plant spe-cies for weed control in various cropping systems (Hedge and Miller, 1990;Purvis, 1990; Hoffman et al., 1996 and Chad et al., 2000). The allelopathic po-tential of Sorghum bicolor L. Moench mulch was examined by Putnam andDeFrank (1983). Purvis et al. (1985) and Cheema and Ahmad (1992) investi-gated allelopathic effects of sorghum on crops and weeds and revealed thatfully ripened sorghum expressed selective allelopathic effects and soil incor-poration of such sorghum residues suppressed the density of Cyperusrotundus by 55 to 94 per cent. The incorporation of sorghum roots (in situ) re-duced dry weight of other weeds (Rumex dentatus, Anagallis arvensis,Phalaris minor, Polygonum bellardii, Chenopodium album and Senebiera didyma)by 26 to 49 per cent. However, sorghum residue promoted the population andgrowth of Melilotus parviflora. Cheema and Ahmad (1992) further reportedthat whole sorghum inhibited the growth of wheat while sorghum root incor-poration increased wheat yield by 5 to 12 per cent over control. In anotherstudy (Cheema et al., 1997) foliar application of water extracts of sorghum andsunflower at 30 days after sowing decreased the dry weight of Rumex dentatisby 74 and 73 per cent, Chenopodium album by 38 and 26 per cent, Cornopusdidymus by 62 and 42 per cent and Fumeria parviflora by 40 and 33 per cent,respectively. Cheema and Khaliq (2000) reported that two foliar sprays ofsorgaab (sorghum water extract) at 30 and 60 DAS reduced total weed dryweight from 38 to 49 per cent. Sorghum stalks that were soil incorporated at 4Mg ha-1 decreased weed dry weight by 48 per cent over the control. The in-crease in wheat grain yield with two sorgaab sprays was 15-21 per cent, whilesorghum stalk incorporation resulted in 16-17 per cent increase in wheat grainyield. Sorgaab sprays in Vigna radiata L. and Brassica juncea L. suppressedweed dry weight by 66% and 85% per cent, respectively (Cheema et al., 2000and Bhatti et al., 2000). Present studies were conducted with the objective ofexploring the possibility of using sorghum allelopathic properties for control-ling weeds in maize grown in a semi-arid environment.

74 JOURNAL OF SUSTAINABLE AGRICULTURE

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MATERIALS AND METHODS

General procedures. Field experiments were conducted to study the effec-tiveness of sorghum allelopathic properties for weed control in maize grown atthe Agronomic Research Area, at the University of Agriculture, in Faisalabad,Pakistan. The soil belongs to the Lyallpur soil series (Aridisol-fine-silty,mixed, hyperthermic Ustalfic, Haplargid in USDA classification and HaplicYermosols in the FAO classification scheme). Sorghum plant herbage washarvested at maturity, air-dried, chopped with a fodder cutter into 2-3 cmpieces and kept under cover to avoid possible leaching by rainwater. Thechaffed sorghum material was either surface applied as mulch or soaked in wa-ter (1:10 w/v) for 24 h at room temperatures (34±2°C). The mixture (herbageand water) was passed through a screen to prepare sorgaab. The seedbed wasprepared by giving two cultivations and planking the field once. Maize wassown manually on moist seedbed using a single row hand drill. Fertilizer wasapplied at 175 kg N, 87 kg P2O5 and 62 kg K2O ha�1 in the form of urea, triplesuper phosphate and sulphate of potash, respectively. Data on weed densityand weed biomass were recorded 20, 40 and 60 days after sowing (DAS) fromtwo randomly selected quadrats (50 cm � 50 cm) from each experimentalplot. Weed dry weight was recorded after drying the weeds in an oven at 80°Cfor 48 h. Data on maize leaf area per plant (cm2) at tasseling, number of cobsper plant, number of grains per row on a cob, 1000-grain weight (g), grainyield (Mg ha�1), stalk yield (Mg ha�1) and harvest index (%) were recordedfor each plot. Weed species observed in the experimental fields were Cyperusrotundus, Trianthema portulacastrum, Cynodon dactylon, Convolvulus arvensis,Dactyloctenium aegyptium and Portulaca oleracea. Data collected were sub-jected to Fisher’s analysis of variance technique. Least significance difference(LSD) test was applied at 0.05-probability level to compare treatments means(Steel and Torrie, 1984).

Experiment 1. A field experiment was conducted during 1997 to study theallelopathic potential of sorghum (Sorghum bicolor L. Moench) plants onweeds and on the growth and yield of maize. Due to rain during the early cropgrowth period during 1997, the foliar sorgaab spraying was delayed to 35DAS. The treatments were control (unweeded check), single spray of sorgaabat 35 DAS, two sprays of sorgaab at 35 and 45 DAS, three sprays of sorgaab at35, 45 and 55 DAS, four sprays of sorgaab at 35, 45, 55 and 65 DAS, two handweedings at 35 and 55 DAS and Pendimethalin (Stomp 330 E) pre-emergencespray at 1.25 kg a.i. ha�1. The volume of spray (300 L ha�1) was calibrated us-ing ordinary water. The experiment was laid out in a randomized completeblock design with four replications in plots measuring 7 m � 3 m. Maize (cv.Golden) was planted in 75 cm spaced rows with a single row hand drill usingthe seed rate of 30 kg ha�1. Sorgaab and Pendimethalin (Stomp 330E) were

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applied in the respective plots using a Knapsack hand sprayer fitted with flatfan nozzle. Hand weeding was done with a hand hoe.

Experiment 2. The effects of sorgaab and sorghum mulch on the growth ofweeds and yield of maize were also compared with hand weeding and chemi-cal herbicides during 1998. This experiment was laid out in a randomizedcomplete block design with four replications. The plot size was 5.5 m � 2.4 m.Maize (cv. Composite-17) was sown in 60 cm spaced rows. The treatmentswere control (unweeded check), sorgaab one spray (15 DAS), sorgaab twosprays (15 and 30 DAS), sorgaab three sprays (15, 30 and 45 DAS), sorghummulch at 10 Mg ha�1, sorghum mulch at 15 Mg ha�1, one hand weeding (15DAS), two hand weedings (15 and 30 DAS), Pendimethalin (Stomp 330 E) at1.5 kg a.i. ha�1, pre-emergence and Atrazine + Metalochlor 2:3 (Primextra500) at 2.0 kg a.i. ha�1, early post-emergence.

Economic analysis. Total cost for all the experimental treatments was cal-culated after determining the field prices of all inputs. Costs that vary (variablecosts) were the costs (ha�1) of purchased inputs, labor, and machinery thatvary between experimental treatments. Yield was adjusted downward (10%)to reflect the difference between the experimental yield and the expected yieldof farmer from the same treatment. Net benefits were calculated by subtractingthe total variable cost from the gross benefits for each treatment (Byerlee,1988). Dominance analysis was carried out by first listing the treatments in theorder of increasing variable costs. Any treatment that had net benefits thatwere less than or equal to those of a treatment with lower variable cost wastaken to be dominated, D (Byerlee, 1988). Finally, marginal analysis was car-ried out to compare the extra (or marginal) costs with the extra (or marginal)net benefits (Byerlee, 1988). For this purpose marginal rate of return (MRR)was calculated by dividing the marginal net benefits (change in net benefit) bythe marginal cost (change in cost) and expressed as a percentage (Byerlee,1988). In the choice of treatments for practical use/recommendation, the dom-inated treatments are dropped due to higher costs involved.

RESULTS AND DISCUSSION

Experiment 1. Data on total weed density (50 DAS) revealed that all thetreatments significantly suppressed weed populations as compared to the con-trol (Table 1). Three sorgaab sprays gave maximum reduction of weed density(40%). Two sorgaab sprays and two hand weedings gave good suppression ofweed density as was recorded for three sorgaab sprays. Cyperus rotundus wasthe major weed and its density was reduced by 30% by three sorgaab sprays.This reduction was statistically similar to that of two sprays of sorgaab, twohand weedings and Pendimethalin treated plots. The reduction in Cyperus

76 JOURNAL OF SUSTAINABLE AGRICULTURE

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rotundus density with sorghum was reported by Cheema and Ahmad (1992).This was possibly due to the allelochemicals present in sorghum. Cheema andKhaliq (2000) also reported weed suppression by sorgaab.

Total dry weight was significantly reduced by all treatments over control(Table 1). Maximum suppression in weed dry weight (38%) was recorded inplots receiving four sprays of sorgaab and was followed by two hand weedings(32%). Two and three sprays of sorgaab suppressed weed dry weight by 20% to23%, respectively, and were statistically on par with Pendimethalin appliedpre-emergence (22%). Cheema et al. (2000) also reported weed dry weight sup-pression due to sorgaab sprays. Four sorgaab sprays increased maize grain yieldby 34% over control, followed by two hand weedings with 32% increase. Threesorgaab sprays improved yield by 12%, while one and two sorgaab sprays didnot influence grain yield (Table 2). Increase in yield under these treatments waspossibly due to better weed control that resulted in improved maize plant heightand grain weight (Table 2). Pendimethalin at 25 kg ha�1 a.i. caused only 6% in-crease in maize grain yield possibly due to less control of Cyperus rotundus byPendimethalin (24%) as compared to three sorgaab sprays (40%).

Economic analysis and marginal rates of return derived from various weedcontrol methods are shown in Tables 3 and 4. It is concluded that four spraysof sorgaab was the best treatment with maximum net benefits of Rs. 19,535ha�1 and with highest marginal rate of return (1723%).

Experiment 2. All the treatments significantly reduced the weed populationas compared to control (Table 5). Three sprays of sorgaab (15, 30 and 45 DAS)proved to be the best among sorgaab treatments and reduced total weed den-sity by 50% as compared to control (Table 5). Primextra at 2.0 kg a.i. ha�1 atearly post-emergence application gave the maximum weed suppression (66%)and was statistically on par with two hand weedings (60%). Sorghum mulch at15 Mg ha�1 caused 37% mortality in weed populations as compared to con-trol. Three sorgaab sprays (15, 30 and 45 DAS) gave 44% mortality inCyperus rotundus and differed significantly from two sorgaab sprays (15 and30 DAS) and the control. Sorghum mulching decreased the density of Cyperusrotundus from 14-23%. Weed suppression through allelochemicals releasedinto soil was reported by Bhowmik and Doll (1984), Cheema et al. (1997), andEinhellig and Rasmussen (1989).

Total weed dry weight recorded at 60 DAS was significantly reduced in allthe treatments over the control except for the one sorgaab spray treatment (Ta-ble 5). Three sorgaab sprays decreased weed dry weight by 55% as comparedto the control (Table 5). Sorghum mulch at 15 and 10 Mg ha�1 suppressed thedry weight up to 44 and 38%, respectively. Primextra at 2.0 kg a.i. ha�1 atearly post-emergence and two hand weedings gave 88% and 71% suppressionin total weed dry weight, respectively. Three sprays of sorgaab reduced the dryweight of Cyperus rotundus by 67%, which was on par with two hand

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weedings (71%) and Primextra (65%). However, sorghum mulching at 10 and15 Mg ha�1 decreased the dry weight of Cyperus rotundus by only 38% and41%, respectively, as compared to control (Table 5). Suppression of C.rotundus density due to sorghum residues was demonstrated by Cheema andAhmad (1992) that was due to release of water-soluble allelochemicals.

All the treatments significantly improved maize grain yield over control(weedy check) but two hand weedings (15 and 30 DAS) gave the maximum(67%) increase in maize yield over control and it was followed by Primextra(58%) and three sorgaab sprays (44%) which were statistically on par with twohand weedings (Table 6). One and two sorgaab sprays increased yield by 18and 32% while Pendimethalin increased yield by 28%. Sorghum mulch at 10and 15 Mg ha�1 increased grain yield of maize by 36 and 40%, respectively,over control. Weeds were suppressed by sorgaab spraying and mulchingwhich reduced weed-crop competition and possibly increased leaf area perplant, number of grains per row and grain weight of maize (Table 6). This ulti-mately resulted in increased grain yield of maize.

Economic analysis of data (Table 7) revealed that two hand weedings gavemaximum net benefits (Rs. 27,960 ha�1) and was followed by Primextra andthree sorgaab sprays with net benefits of Rs. 25,655 and Rs. 25,260 ha�1, re-spectively. Marginal rates of return (MRR) derived from various treatments(Table 8) showed that one sorgaab spray (15 DAS) had the highest MRR

Research, Reviews, Practices, Policy and Technology 81

TABLE 4. Dominance and Marginal Analysis of Different Weed Control Meth-ods in Maize (Experiment 1)

Treatments Cost that vary(Rs. ha�1)

Net benefit(Rs. ha�1)

Marginal rateof return (%)

Control 0 14850

One sorgaab spray (35DAS**)

190 14661 D*

Two sorgaab sprays (35and 45 DAS)

380 14470 D

Three sorgaab sprays (35,45 and 55 DAS)

570 16260 247

Four sorgaab sprays (35,45, 55 and 65 DAS)

760 19535 1723

Two hand weedings (35and 55 DAS)

2000 17800 D

Pendimethalin pre em. @1.25 kg ha�1 a.i.

2550 13290 D

*Dominated; **Days after sowing; Rs. = Rupees.

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(1613%) and was followed by two sorgaab sprays (1263%), three sorgaabsprays (968%) and two hand weedings (188%). Herbicidal treatments(Primextra and Pendimethalin) and sorghum mulch treatments and one handweeding were less economically feasible due to higher costs involved and rel-atively lower net benefits.

In conclusion, these studies revealed that three foliar sprays of sorgaab andsorghum surface mulching were quite effective in suppressing the density anddry weight of weeds. Three and four sprays of sorgaab were much more eco-nomical to apply than sorghum surface mulching and appear to control weedsto a considerable extent in summer maize.

REFERENCES

Ahmad, S., Cheema, Z. A. and Mahmood, A. 1991. Response of some rabi weeds andwheat to allelopathic effects of irrigated sorghum in a sorghum wheat cropping sys-tem. Pak. J. Weed Sci. Res. 4: 81-88.

Alsaadawi, I. S., Al-Uqaili, J. K., Alrubeaa, A. J. and Al-Hadithy, S. M. 1986.Allelopathic suppression of weeds and nitrification by selected cultivars of Sor-ghum bicolour (L.) Moench. J. Chem. Ecol. 12: 209-219.

Bhatti, M. Q. L., Cheema, Z. A. and Mahmood, T. 2000. Efficacy of sorgaab as naturalweed inhibitor in Raya. Pak. J. Bio. Sci. 3: 1128-1130.

Byerlee, D. 1988. From agronomic data to farmers recommendations. An EconomicsTraining Manual. CIMMYT. Mexico 30-33.

Research, Reviews, Practices, Policy and Technology 85

TABLE 8. Marginal Analysis of Sorgaab and Sorghum Mulch for Weed Controlin Maize (Experiment 2)

Treatments Cost that vary(Rs./ha)

Net benefit(Rs./ha)

Marginal rateof return (%)

Control 0 17955

One sorgaab spray (15 DAS*) 190 21020 1613

Two sorgaab sprays (15 and 30 DAS) 380 23420 1263

Three sorgaab sprays (15, 30 and 45 DAS) 570 25260 968

One hand weeding (15 DAS) 1000 21750 D**

Two hand weedings (15 and 30 DAS) 2000 27960 188

Pendimethalin @ 1.5 kg ha�1 a.i. pre-em. 2550 20480 D

Primextra @ 2.0 kg ha�1 a.i. early post-em. 2625 25655 D

Sorghum mulch @ 10 Mg ha�1 5400 18960 D

Sorghum mulch @ 15 Mg ha�1 7500 17160 D

*Days after sowing; Rs. = Rupees. **Dominated.

Dow

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Pak

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at 0

2:35

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015

Cheema, Z. A., and Khaliq, A. 2000. Use of sorghum allelopathic properties to controlweeds in irrigated wheat in a semi-arid region of Punjab. Agriculture, Ecosystemsand Environment 79:105-112.

Cheema, Z. A., Sadiq, H. M. I. and Khaliq, A. 2000. Efficacy of sorgaab (sorghum wa-ter extract) as a natural weed inhibitor in wheat. Int. J. Agri. Biol. 2:144-146.

Cheema, Z. A., and Ahmad, S. 1992. Allelopathy a potential tool for weed manage-ment. National seminar on the role of plant health and care in Agricultural produc-tion on Dec. 28-29, 1988 at Univ. Agric., Faisalabad, Pakistan.

Cheema, Z. A., Rakha, A. and Khaliq, A. 2000. Use of sorgaab and sorghum mulch forweed management in Mungbean. Pak. J. Agric. Sci. 37:140-144.

Cheema, Z. A., Luqman, M. and Khaliq, A. 1997. Use of allelopathic extracts of sor-ghum and sunflower herbage for weed control in wheat. J. Animal Plant Sci. 7:91-93.

Einhellig, F. A., and Rasmussen, J. A. 1989. Prior cropping with grain sorghum inhib-its weeds. J. Chem. Ecol. 15: 951-960.

Hedge, R. S. and Miller, D. A. 1990. Allelopathy and autotoxicity in alfalfa: Character-ization and effects of preceding crops and residue incorporation. Crop Sci. 30:1255-1259.

Hoffman, M. I., Weston, I. A., Synder, J. C. and Regnier, E. E. 1996. Separating the ef-fects of sorghum (Sorghum bicolor) and rye (Secale cereale) root and shoot resi-dues on weed management. Weed Sci. 44: 402-407.

Purvis, C.E., Jessop, R. S. and Lorett, J. V. 1985. Selective regulation of germinationand growth of annual weeds by crop residues. Weed Res. 25: 415-421.

Putnam, A. R., and Defrank, J. 1983. Use of phytotoxic plant residues for selectiveweed control. In Proc. Br. Crop. Prot. Conf. Weeds 2: 173-181.

Putnam, A. R., and Duke, W. A. 1974. Biological suppression of weeds: Evidence forallelopathy in accessions of cucumber. Science 185: 370-372.

Steel, R. G. D., and Torrie, J. H. 1984. Principles and Procedures of Statistics. 2nd ed.McGraw Hill Book Co. Inc., Singapore.

RECEIVED: 06/10/02REVISED: 12/30/02

ACCEPTED: 01/23/03

86 JOURNAL OF SUSTAINABLE AGRICULTURE

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